In vehicles, a parking brake, sometimes also called an emergency brake, is a latching brake usually used to keep the vehicle stationary. It is sometimes also used to prevent a vehicle from rolling when the operator needs both feet to operate a clutch and throttle pedals. Automobile parking brake systems usually consist of a cable directly connected to the parking brake on one end and to a manually moveable mechanism at the driver's position. The mechanism is typically a hand-operated lever on either side of the driver, a pull handle located below and near the steering wheel column, or a foot-operated pedal located adjacent other foot-pedals.
In vehicles with rear drum brakes, a parking brake cable is used to actuate the drums of the drum brakes mechanically with less force than may be available through the regular hydraulic system. In vehicles with rear disc brakes, the parking brake either actuates the disc calipers via a cable or a small drum brake housed within the hub assembly (the inner circumference of the rotor is often used instead of a separate drum; sometimes referred to as a drum-in-hat rotor).
Electronic parking brakes may use an electric switch for activation/deactivation of the parking brake as opposed to the manually moveable mechanism. To its obvious advantage of only having a small switch within drivers reach versus a larger mechanism, it also has the disadvantage of not backfeeding a force, displacement, or activation feel, or for providing a modulation of the brake force being applied. With this disadvantage, having only a switch makes it impossible to use the parking brake to aid in launching a boat, enhance sporty driving whilst using the handbrake during turns, and also does not give the customer the feel of having their vehicle properly secured during parking.